title: The impact of smoking on thromboembolism and mortality in patients with incident atrial fibrillation: insights from the Danish Diet, Cancer, and Health study.
abstract: BACKGROUND
  Smoking and atrial fibrillation (AF) are major health problems worldwide and are responsible for substantial health-care costs. Our aim was to investigate whether smoking impacts the risk of stroke and death in patients with AF. To test this hypothesis, we analyzed data from a large Danish cohort: the Diet, Cancer, and Health study.
  
  
  METHODS
  This was a cohort study of 57,053 people (27,178 men; 29,876 women) aged 50 to 64 years. The risk of thromboembolism (ischemic stroke/arterial thromboembolism) or death according to smoking habits among 3,161 patients with incident AF (mean age, 66.9 years; 2,032 men, 1,129 women) was assessed using Cox proportional hazard models after a median follow-up of 4.9 years.
  
  
  RESULTS
  Of those with AF, 34% were current smokers and 37% former smokers. After adjustment for vitamin K antagonist treatment, the hazard ratios (HRs) (95% CI) of thromboembolism or death were 3.13 (1.72-6.37) and 2.73 (2.02-3.70) among women and men who currently were heavy smokers (>25 g/d), respectively. The associations remained after adjustment for well-established risk factors with HRs of 3.64 (1.88-7.07) and 2.17 (1.59-2.95) among women and men, respectively. In a sensitivity analysis, smoking was still strongly associated with thromboembolism or death after censoring people with a cancer diagnosis during follow-up.
  
  
  CONCLUSIONS
  Smoking is associated with a higher risk of thromboembolism or death in patients with AF even after adjusting for well-recognized risk factors used in stroke risk stratification schemes. The associations may be modified by sex, as the associations were strongest among women.
authors.forename: Ida Ehlers
authors.initials: IE
authors.lastname: Albertsen
authors.forename: Lars Hvilsted
authors.initials: LH
authors.lastname: Rasmussen
authors.forename: Deirdre A
authors.initials: DA
authors.lastname: Lane
authors.forename: Thure Filskov
authors.initials: TF
authors.lastname: Overvad
authors.forename: Flemming
authors.initials: F
authors.lastname: Skjøth
authors.forename: Kim
authors.initials: K
authors.lastname: Overvad
authors.forename: Gregory Y H
authors.initials: GY
authors.lastname: Lip
authors.forename: Torben Bjerregaard
authors.initials: TB
authors.lastname: Larsen
mesh_terms: D001281:Atrial Fibrillation / Q000150:complications* / Q000401:mortality; D002423:Cause of Death / Q000639:trends; D003718:Denmark / Q000453:epidemiology; D004032:Diet; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D011446:Prospective Studies; D012042:Registries; D012307:Risk Factors; D012907:Smoking / Q000009:adverse effects* / Q000401:mortality; D013923:Thromboembolism / Q000453:epidemiology* / Q000209:etiology / Q000517:prevention & control; D013997:Time Factors